1. Field of the Invention
The present invention relates generally to user interfaces for video editing applications, and more particularly to a user interface that provides expandable and collapsible layers for organizing, viewing, and manipulating a video project.
2. Background of the Invention
Most video editing software applications provide some sort of timeline view of the video project. Conventionally, a timeline view is a graphical representation showing a number of video clips and their arrangement within the video project. For example, a horizontal timeline may be established, with each video clip being represented by a horizontal bar that provides a visual indication of the start and end points of each clip within a time axis. A user can manipulate the horizontal bar to shorten, lengthen, move, or edit the video clip.
In most video editing programs, such as Final Cut Pro, available from Apple Computer Corp. of Cupertino, Calif., clips are depicted on a single horizontal row; an example of such an arrangement is shown in FIG. 1A. Row 100 includes bars representing four clips 101A through 101D. The user can drag clips 101A through 101D to move them to other locations within the timeline represented by row 100.
Such an approach, which is common in most video editing programs, makes it difficult to distinguish between overlapping clips and sequentially arranged clips. Since all clips are shown on row 100, overlapping (such as for example if one clip fades into another, or if clips are superimposed upon one another) is not immediately visible from the timeline. In addition, in cases where clips are superimposed on one another, so that they occupy a common location in row 100, one clip 101 may be obscured from view if it is hidden underneath another clip 101 within row 100. If a large number of superimposed clips are provided, the arrangement of FIG. 1A can make it difficult to view and manipulate clips 101, or to understand the relationship among the clips 101, or even to see which clips 101 are present.
Programs such as Final Cut Pro allow nesting of clips 101 into a single aggregated timeline bar 201, as shown in FIG. 1B. Timeline bar 201 represents the four clips 101A through 101D that were shown in FIG. 1A. If the user wishes to edit individual clips 101A through 101D when timeline bar 201 is displayed, the user must expand bar 201 (typically by double-clicking on it) to return to a screen similar to FIG. 1A, which allows individual clips 101A through 101D to be manipulated and/or edited. Thus, although timeline bar 201 offers a more streamlined view of the video project, it does not allow for direct editing of its component clips 101, forcing the user to switch between views in order to perform editing operations.
Other software applications, particularly compositing applications such as After Effects, available from Adobe Corp. of San Jose, Calif., provide multiple rows for displaying video clips within a timeline; an example of such an arrangement is shown in FIG. 2A. Here, a separate row 100A through 100D is provided for each clip 101A through 101D. In general, each clip 101 is displayed in its own horizontal row 100. Such an arrangement more clearly shows the relationships among clips 101, and in particular shows distinctions between overlapping clips 101 and sequential clips 101. However, such an arrangement can become cumbersome when, for example, the video project includes a large number of clips 101 in sequence; the timeline display can become excessively deep in the vertical direction, since a separate row 100 is generated for each clip 101.
Programs such as After Effects allow clips 101 to be collapsed into a single aggregated timeline bar 201, as shown in FIG. 2B. This timeline bar 201 is referred to as a “nest.” However, as with the technique depicted in FIG. 1B, such an arrangement does not provide any indication of the contents of bar 201, and does not provide any mechanism for directly editing those contents. In order to edit individual clips 101, the user must expand timeline bar 201 (typically by double-clicking on it) to return to a screen similar to FIG. 2A, which allows individual clips 101A through 101D to be manipulated and/or edited.
The user can click on expand button 401 to show a screen similar to FIG. 2C, which allows editing of certain properties of timeline bar 201. However, as shown in FIG. 2C, the only properties that can be edited are master attributes 501 such as global position, scale, rotation, and the like. No provision is made for editing individual clips 101 of bar 201 without first expanding bar 201 to display a screen such as FIG. 2A.
Some programs, such as Combustion, available from Discreet of Montreal, Quebec, Canada, provide a display that includes both an aggregated timeline bar 201 and separate rows for displaying clips 101A through 101D. An example of such a display is shown in FIG. 3A. Clips 101A through 101D can be collapsed into bar 201, resulting in a display such as shown in FIG. 2B. Here, as in the previously discussed prior art examples, the collapsed bar 201, whether shown together with separately displayed clips 101A through 101D as in FIG. 2A or on its own as in FIG. 2B, does not permit direct editing of clips 101. Thus, as with the previous examples of prior art techniques, there is no way for the user to directly edit individual clips 101A through 101D within bar 201.
What is needed is a technique that combines the benefits of a single timeline bar with those of the multiple-row approach, while avoiding the detrimental aspects of each technique. What is further needed is a user interface that provides a single-bar view of a number of clips on a single horizontal row while still allowing direct editing of clips within the row. What is further needed is a user interface that provides maximum visibility, control, and manipulability of video clips without occupying excessive screen space and without forcing the user to switch between collapsed and expanded modes.